Hoisting equipment



July 5, 1960 M. F. SAISGEN noxsmc EQUIPMENT 2 Sheets-Sheet 1 Filed Feb.9, 1959' INVENTOR. MATTHIAS F. SASGEN y y l Ma/m/M ATTORNEYS y 1960 M.F. SASGEN 2,943,708

HOIS'iING EQUIPMENT Filed Feb. 9, 1959 2 Sheets-Sheet 2 INVENTOR.MATTHlAS F. SASGEN ATTORNEY;

United States Patent HOISTING EQUIPMENT Matthias F. Sasgen, RiverForest, 11]., assignor to Sasgen Derrick Company, Chicago, 11]., acorporation of Illinois Filed Feb. 9, 1959, Ser. No. 792,154

2 Claims. (Cl. 187-85) This invention relates to a safety device forhoisting equipment of the kind wherein the platform is arranged for upand down movement on a substantially upright frame, and the safetydevice is one which is adapted to hold the plaform in the event that thehoisting cable should break.

Safety devices of one kind or another are commonly employed inassociation with platform hoists wherein the platform is usuallyelevated by a cable, the safety taking over in the event that the hoistcable should break. In those instances where the frame which affords thevertical guide for the platform is of ferrous metal, the safety deviceusually takes the form of a toothed eccentric which is mechanicallyarranged to take a tight hold on the frame itself in the event thehoisting cable should break. In this instance, the toothed eccentric orother toothed holding device actually bites into the frame, but sincethe frame is of steel or the like there is very little likelihood ofdamage to the frame.

In recent years, however, resort has been had to frames constructed ofaluminum for hoisting apparatus. Aluminum, in a manner of speaking, isrelatively soft, and it is found that the conventional safety devicementioned above for use in connection with steel frames, is ineffectiveon aluminum. Thus, there is little or no assurance that the safetydevice which is intended to in efiect grasp the frame will be effectiveon an aluminum frame, and in fact it is very likely that such a safetywill slip rather than grab on aluminum, turning and twisting thealuminum frame.

In view of the foregoing it is an object of the present invention todevise a safety specifically adapted to grab a safety cable rather thanthe frame of hoisting apparatus fabricated primarily from aluminum.Thus, a safety in the present instance is one that comprises aneccentric disposed on one side of a safety cable, and a back-up memberdisposed on the other side of thecable. Both the eccentric and theback-up member are carried by the platform, and the cable is at leastanchored near the top of the aluminum frame. A crank is afforded, forthe eccentric, this crank being normally effective to position theeccentric with a low part thereof presented to the safety cable so longas the hoisting cable or other flexible lifting element is eifective toraise or hold the platform. In the event that the flexible liftingelement should break, means are effective to operate the crank topresent a high part of the eccentric to the cable, causing the cable tobe squeezed between the eccentric and the back-up member. When thisinitial safety condition is established, any further drop of theplatform is instantaneously characterized by a servo-action of theeccentric such that practically instantaneously the eccentric iseffective in cooperation with the back-up member to tightly grab thesafety cable, and this condition is maintained by the weight of theplatform itself.

It has heretofore been proposed to construct a safety including a safetycable .and a cooperating eccentricand 2,943,708 Patented July 5, 1960back-up member. However, prior constructions of this general kind havemany deficiencies and are generally impractical in connection withheavy-duty hoisting apparatus of the kind presently under consideration.Accordingly, it is a specific object of the present invention to devisea safety of the general kind mentioned above having improved operatingcharacteristics particularly in respect of the crank which is to operatethe eccentric and the spring element which is to deliver the initialimpulse for actuating the crank.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by way of illustration, show preferredembodiments of the present invention and the principles thereof and whatis now considered to be the best mode contemplated for applying theseprinciples. Other embodiments of the invention embodying the same orequivalent principles may be used and structural changes may be made asdesired by those skilled in the art without departing from the presentinvention and the purview of the appended claims.

In the drawings:

Fig. l is a perspective view of hoisting apparatus of the kindcontemplated by the present invention;

Fig. 2 is a fragmentary elevation of one form of safety link constructedin accordance with the present invention;

Fig. 3 is a fragmentary elevation of another form of safety linkconstructed in accordance with the present invention; and

Fig. 4 is a fragmentary elevation showing details of actuation of aclamping eccentric. 1

Hoisting apparatus of the kind contemplated is illustrated in Fig. 1.This particular hoist includes, in its operative position, a generallyupright frame 10 having parallel guide members 11 and 12. The guidemembers 11 and 12 are of extruded aluminum, and these are braced andspaced by cross members as 13 in the usual fashion.

The uprights 11 and 12 constitute guides for a platform 15 whichincludes a pallet 16 supported by arms 17 that are disposed in agenerally horizontal plane and project outward substantially at rightangles from the upright guides 11 and 12. The platform 15 additionallyincludes a pair of vertical arms as 18, and these arms are provided withguide rollers 19 which fit in outside channels formed in the uprights 11and 12. It will be noted that the rollers 19 turn on axes that aregenerally parallel to the pallet support arms 117. It should bementioned that the arms 18 have other rollers (not shown) which rotateon axes that are normal to the axes for the rollers 19, and these otherrollers fit neatly within the outside channels in the uprights 11 and 12so as to be substantially in engagement with the inside faces of theflanges F of the uprights. Thus, it will be recognized that the rollersmentioned stabilize the platform on the frame 10 and at the same timeprovide for anti-friction movement of the platform on the frame.

The platform 15 is raised and lowered by a flexible lift element in theform of a hoist cable 20. This cable is wound and unwound from a cablewinder 21 which is anchored in place on a motor base 22 which in turn isanchored to a horizontal relatively expansive stabilizing base 25 whichis the primary stabilizer for the frame 10. The winder 21 is powered byan internal combustion engine 30. The hoisting cable 20 extends upwardalong the length of the frame 10 and is played over a pulley 31 which issupported at the top of the frame 10. The hoist cable 20 is connected toa sheave or block 32, and this sheave or connector in turn is attachedto the lift head v35.01:.the platforr'nlS, tDifferent .pounections can-of 'In this connection it will be noted that the hoisting apparatusillustrated in Fig. 1 includes a pair of elongated arms 40 and 41 whichare attached at their upper ends to the guide members 11 and 12, thepoints of attachment being somewhat below the top of the frame. Thesearms extend downward from their points of attachment at a divergentangle relative to the guides 11 and 12, and the lower ends of the arms40 and 41 are joined to the primary stabilizing base 25 by connectors as42 and 43. The arms 40 and 41, and the connectors 42 and 43 are placedrelative one to another and are also placed against the guides 11 and12.

An axle 45 is supported by the connectors as 42, and wheels 46 in turnare supported by the axle 45. A conventional hitch 47 is attached to thetop of the frame 10. Pivotally attached to the arms 40 and 41 are a pairof auxiliary stabilizer arms 47 and 48. These auxiliarystabilizers haveground engaging pads 47F and 48F. The manner of pivotally attaching theauxiliary stabilizers 47 and 48 to the arms 40 and 41 is such as toenable the stabilizers 47 and 48 to be turned upward in acounterclockwise direction as viewed in Fig. ;l*to a folded statesubstantially parallel'with the arms 40 and 41, and means (not shown)are employed to enable the stabilizers to be releasably secured intheir'folded state. When so folded,

the stabilizers '47 and 48 enable the holdingapparatus to be turnedclockwise as viewed in Fig. 1 about the connectors 43, and it should bementioned that these connectors are located in a plane that is inclinedupwardly 'out of the plane of the primary stabilizer base 25, and

this facilitates tilting of the apparatus. Once tilted, the

-wheels 46 eventually are effective to support the apparatusforconvenient towing through the hitch 47.

It will be appreciated that the platform 15 will'be used to raisematerials or equipment to an elevated position 'when the hoistingapparatus is in use, and of course a workman may also ride on theplatform 15. In any event it becomes important to provide some form ofsafety in the event that the hoisting cable should break. In accordancewith the present invention such safety feature is represented byan'eccentric clamp, the details of operation of which will be explainedhereinafter, and which cooperates with a safety cable ,50 which isconveniently anchored at its upper end near the top of the frame 10. Thelower end of the safety cable 50 can be conveniently secured to thelower base mounting 22.

It will be observed-in Fig. 1 that safety cable 50 is located adjacentone side of the lift head 35 that is includedas a part of the platform15, and of course it will be realized that the safety cable isstationary and that the platform 15 moves up and down relative thereto.In accordance with the present invention, a clamping disc 53, Fig. 4, ismounted for rotation on an eccentric axis, and this axis is representedby a ,pin 54, Fig. 4, which in turn is supported by a mounting bracket55, which in turn is fixed on the upper end of the platform lift head35. Thus, the bracket 55 includes a rectangular vertical leg 56 which iswelded or otherwise secured to the lift head 35, and the bracket 55 isformed with a horizontal leg 57 which extends slightly over theeccentric 53 so as in effect to constitute a protective cover therefor.The horizontal leg 56 is formed with an aperture 57A, and the safetycable 50 is passed therethrough. Thus, it will be seen that theeccentric 53 and its mounting bracket 55 move with the lift head 35. Itought also to be pointed out that the bracket 55 includes a back-upplate 59 which is disposed in vertical relationship with the bracket 55and which lies near the safety cable 50. The back-up plate 59 representsan important element of the safety clamp as will be explainedhereinafter. It

should also be mentioned that the platform 15 is raised and lowered by ahoisting cable 20, and it will be, noted that this cable is alsoidentified in Fig. 2. A connector of one kind or another is attached tothe end of the cable 20 which is used to elevate the platform 15, andthis connector serves as an intermediate member joining the hoistingcable to the lift head of the platform. Thus, in Fig. 2, a connectortakes the form of an inactive sheave 61. The end of the sheave 61opposite that joined to the hoisting cable is secured to an elongatedeye bolt 62, and this bolt is passed down through an aperture formed inthe horizontal flange 35H of the lift head 35, noting that the lift head35 in the present invention is disclosed as being in the form of anangle bar. The threaded end of the eye bolt 62. extends to. a pointdisplaced well below the lower edge of the lift head 35. A tubularsleeve 63 is arranged concentric to the portion of the shank of the eyebolt 62 which extends below the flange 35H of the lift head, and thecoil spring 65 is arranged concentric to this portion of the eye bolt,shank in the space between the eye bolt shank and the sleeve '63. A oflock nuts as 67 are threadedly mounted on the lower end of the eye bolt62, and a washer 70 is interposedibetween the nuts 67 and the lower endof the sleeve 63. Thus, the arrangement is one wherein theconnectorrepresented by the sheave 61 and the eye bolt 62 is effectiveto raise the platform 35 through the spring 65', and under suchcircumstances the spring 65 will normally be substantially fullycompressed so as in effect to con stitute a resilient block between theconnector means and the lift head of the platform.

The clamping eccentric 53 is controlled by a crank structure which iscarried between connector means. Thus, as shown in Fig. 2 a rigidhorizontal arm 70 is welded to the portion of the eye bolt 62 whichprojects above the lift-head 35. The arm 70 extends toward the bracket55 which carries the eccentric, but terminates short of the bracket 55.Referring to Fig. 4, a crank link 72 has its inner end firmly joined'toa point on the eccentric 53 below the axis pin 54. The opposite end ofthe crank link 72 extends free of the disc 53, and an intermediateoperating link 74 is pivotally connected to the adjacent ends of the arm70 and the crank link 72.

In the event that the hoisting cable 20 should break, lifting forcesotherwise effective on the cable 20are dissipated insofar as theplatform is concerned, and hence the platform 15 will undergo normally afree fall; however, and at the same time, a coil spring 65 which waspreviously under compression will now expand to the dotted linecompression shown in Fig. 2. Concurrently with this, arm 70 drops, andbecause of the angular relationships involved between the links 72 and74, the operating link 74 tends to assume a horizontal position, and theresultant forces are translated into counter-clockwise rotary motion ofthe disc 53. Accordingly, instead of a low part of the eccentric beingpresented to the safety cable as under normal or ordinary circumstances,a high part of the eccentric is turned into engagement with the safetycable 50, pushing the safety cable against the backup plate 59. Itshould be mentioned that the spring 65 -or other resilient startingelement, simply initiates the operation of the crank structure, becauseonce there is effective friction between the disc 53, the safety cable50 and the back-up plate 59, the weight of the platform comes into play,and a servo force is established causing the eccentric 53 to grip thesafety cable 50 tighter and tighter. The final holding force reallybecomes the weight of the platform. In an actual test, wherein thehoisting cable was burned through by a torch, the platform 15 droppedonly three inches during the time that the above servo action was takingplace.

Various forms of construction can be resorted to insofar as an effectiverelationship is concerned between the connector means and the springmeans used to start operation of-the clamping eccentric. Thus, referringto Fig.

3 a doubled hoisting line 20A is utilized in connection with thecompletely effective sheave 61A. In other words, the hoisting cable 20Ain this instance is conventionally associated with the pulley 61A. Thehorizontal arm of the crank operating structure is of somewhat longerlength and is indicated at 70A in Fig. 3. Plate 80 is secured to thesheave 61A, and this plate has an end projecting below the sheave 61A,and a bolt 81 is used to join the arm 70A to the plate 80. A pair ofconventional bolts 82 and 83 are inserted in corresponding apertures inthe arm 7 0A with the heads thereof reposing on the upper surfaces ofthe arm 70A. The bolts 82, 83 are centered in either side of the arm 70Aand the plate 80, and the shanks thereof are passed through a pair ofapertures in the horizontal flange of the lift head 35. The tube, coilspring and lock nut arrangement described above in connection with Fig.2 is repeated for each of the bolts 82 and 83, but instead of a washer70 there is used a common crosshead 90 interposed between the two setsof lock nuts and the two sleeves 83.

It will be recognized that the operating principles for the structureillustrated in Fig. 3 are substantially the same as shown in Fig. 2.Thus, if the hoisting cable 20 should break, the two previouslycompressed coil springs associated with bolts 82, 83 will expand andconcurrently the horizontal arm 70A is pulled down, causing theintermediate link 74 to move to a substantially horizontal positionthereby efiectively driving the crank link and causing virtuallyinstantaneous rotation of the eccentric 53 whereby a clamping force onthe cable 50 is generated in the manner described above.

It will be seen from the foregoing that under the present inventionthere is afforded a safety clamp or hoisting apparatus of the kind usinga main frame constructed from aluminum which is a relatively softstructural material compared to steel. Thus in the present instance thesafety clamp is associated with a safety cable rather than one that iseffective on the frame itself. Relatively few operating parts areinvolved, and for the most part advantage is taken of an essentialstructure that will of necessity already be present. Thus, the presentarrangement takes advantage of a sheave or other connector that isalready interposed between the flexible lifting cable and the lift headof the working platform of the hoisting apparatus. Moreover, there arebut few parts required to render the eccentric effective, and theseinclude the backup plate on one side of the safety clamp, two links forrotating the eccentric, and an arm which is fixed to the connector foractuating the links. The arm which actuates the links only comes intoplay in the event that the hoisting cable should break whereupon theconnector and e the arm 70 or 70A associated therewith are pulled downby the coil spring undergoing expansion.

Hence, while I have illustrated preferred embodiments of my invention,it is to be understood that these are capable of variation andmodification, and I therefore do not wish to be limited to the precisedetails set forth, but desire to avail myself of such changes andalterations as fall within the purview of the following claims.

I claim:

1. In hoisting apparatus of the kind described, means affording a frameadapted to be disposed in a substantially upright attitude, a platformmounted on the frame for up and down movement, said platform including alift head, means to raise and lower said platform including a flexiblelift element, a connector joined to said lift element to be liftedthereby, a coil spring having one end backed up by said lift head andhaving the other end thereof joined to said connector whereby liftingforces are imparted to said lift head by lost motion through said springcausing compression of the spring, a safety cable having an upper endanchored near the top of said frame and said cable extending downwardtoward the bottom of said frame, a rigid back-up member carried by saidlift head and disposed on one side of said safety cable, a rotatableeccentric carried by said lift head and located on the other side ofsaid safety cable, and a crank for the eccentric carried by saidconnector, said crank including a substantially horizontal arm having aportion rigidly secured to said connector and a crank link having aportion connected to said eccentric and an intermediate link pivotallyinterconnecting the horizontal arm and the crank link, and said crankhaving a stroke that rotates the eccentric to present a low part of theeccentric to the safety cable when said connector is efiective tocompress said spring and which presents a high part of the eccentric tothe safety cable, pressing the safety cable against said back-up member,when said spring expands.

2. In hoisting apparatus of the kind described, means affording a frameincluding aluminum guide members adapted to be disposed in asubstantially upright attitude, a platform mounted on the guides for upand down movement, said platform including a lift head, means to raiseand lower said platform including a flexible lift element, a connectorjoined to said lift element to be lifted thereby, said connector beingprojected through said lift head and terminating at an end disposed wellbelow the lift head, a coil spring located under the lift head andhaving an upper end backed up by said lift head and having the lower endthereof joined to said end of said connector whereby lifting forces areimparted to said lift head by lost motion through said spring causingcompression of the spring, a safety cable having an upper end anchorednear the top of said frame and said cable extending downward toward thebottom of said frame, a rigid back-up member carried by said lift headat one side thereof and disposed on one side of said safety cable, arotatable eccentric carried by said lift head and located on the otherside of said safety cable, and a crank for the eccentric carried by saidconnector, said crank including a substantially horizontal arm anchoredto said connector and extending toward but terminating short of saideccentric, a crank link connected to said eccentric for turning theeccentric, and an intermediate operating link pivotally interconnectingsaid arm and said crank link at an angle, whereby said angle is changedcausing turning of the eccentric when said horizontal arm is raised orlowered with said connector relative to said lift head.

References Cited in the tile of this patent UNITED STATES PATENTS592,698 Cox Oct. 26, 1897 922,452 Burgan May 25, 1909 1,015,137 ClarkJan. 16, 1912 1,038,961 Rivers Sept. 17, 1912 1,252,122 Jewell Jan. 1,1918

